Method and circuit for telegraphic impulses



Feb. 4, 1941.

E. FRISCHKNECHT METHOD AND CIRCUIT FOR TELEGRAPHIC IMPULSES Filed May28, 1937 4 Sheets-Sheet l IMPULSES RELAY A OPERATED- FIG. 4

42 9.5; RELAY R OPERATED FIG. 5

INVENTOR ERNEST FRISCHKNECHT NEY ATT

Feb. 4, 1941. E. FRISCHKNECHT I METHOD AND C IRCUIT FOR TELEGRAPHICIMPULSES Filed May '28, 1957 4 Sheets-Sheet 2 FIG.8

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INVENTOR ERNEST FR ISCH KN ECHT BY aifi -w AT ORNEY E. FRISCHKNECHTMETHOD AND CIRCUIT FOR TELEGRAPHIC IMPULSES Filed May 28, 1957 Feb. 4,1941. 2,230,681

4 Sheets-Sheet 3 TD FIG. IO 28 FIG. :2

v FIG. I3

INVENTOR ERNEST FRISCH KN ECHT ATTORNEY 1941- V E. FRISCHKNECHT2,230,681

METHOD AND CIRCUIT FOR TELEGRAPHIC IMPULSES Filed May 28, 1937 4Sheets-Sheet 4 FIG. l4

LINE3 LINE2 LINE I INVENTOR ERNEST FR SCHKNECHT BY v AT ORNEY PatentedFeb. 4, 1941 UNITED STATES PATENT OFFICE METHOD AND CIRCUIT FORTELEGRAPHIG IMPULSES Application May 28, 1937, Serial No. 145,204

10 Claims.

This invention relates to improved methods and circuits for telegraphicimpulses and improved operation of electro responsive apparatuscontrolled thereby. I

In systems heretofore devised for transmitting and repeating telegraphicimpulses by means of repeating relays and the like, the first impulsetransmitted by the repeating relays is of shorter length than succeedingimpulses of a series of impulses thereby causing failure of thereceiving apparatus to operate in response to the first impulse of theseries.

In systems for transmitting and repeating telegraphic impulses, whichemploy repeating relays operating from a constant length signal such as,

of example, the signal received from a transmitting distributor havinguniformly spaced transmitting segments to transmit a series of signals,it has been found that the spacing between the first signal and thesecond signal transmitted by the relays is less than the spacing betweenthe second and all succeeding signals transmitted.

This condition, which is present in an arrangement such as shown in Fig.5 of the drawings herein, is caused by the relays requiring a longertime to operate when the first impulse of a series is received than whensucceeding impulses of the series are received due to the residualmagnetism of the relay being near the zero value at the start of thefirst impulse and at some value considerably above this first value atthe start of each of the succeeding impulses. The time required tooperate the relay when the first impulse is received is thereforegreater than the time required to operate the relay on the succeedingimpulses of a series.

Similarly in automatic quotation systems heretofore devised which employelectro magnetic indicator units for posting the quotations, it has beenfound that these indicator units fail to operate when the first impulseis received due to insuflicient time between the end of the firstimpulse and the start of the second impulse within 45 which time thearmature of the indicator unit must release. This foreshortening of therest interval between the first impulse and succeeding impulses iscaused by the failure of the repeating relays controlling the indicatorunit to 50 operate as quickly when the first impulse is received as whensuccessive impulses are received thereby to foreshorten the non-currentinterval of the indicator unit signal between the first and secondimpulse.

55 One of the objects of the invention is provision of means forcontrolling the lengths of outgoing impulses and for maintaining them inuniformly spaced relationship one from the other.

Another of the objects of the invention is the provision of an improvedcircuit for operating 5 electroresponsive devices by means of a seriesof impulses whereby the electroresponsive device receives more currentduring the first impulse of the series than during the succeedingimpulses.

Another object of the invention is the provision 10 of means forapplying a biasing current to the winding of an electroresponsive deviceprior to or concurrently with the reception of the first impulse of aseries and thereafter removing the biasing current from the deviceduring the re- 15 ception of the first impulse and until all otherimpulses of the series are received.

A still further object of the invention is an arrangement of circuitscomprising a transmitting distributor or the like for initiating aseries 20 of uniformly spaced impulses of equal length whereby theseries of impulses repeated by the relays of the circuit are all uniformin length and uniformly spaced one from the other.

Other objects of the invention will appear from the followingdescription taken in connection with the drawings in which:

Fig. 1 is a view of a regenerator unit, parts of the frame mechanismbroken away.

Fig. 2 is a view of the two armatures employed with one of the relays ofFig. 1, along the line 2-2.

Fig. 3 is a diagram showing the lengths of incomirgg and outgoingimpulses of the relays of Fig.

Fig. 4 shows the lengths of incoming and outgoing impulses of the relaysof Fig. 6.

Fig. 5 is a circuit of the pair of relays employed with the diagram ofFig. 3.

Fig. 6 is a circuit diagram illustrating one form of the presentinvention.

Fig. 'l is a diagram of the impulses received from the distributor ofFig. 6.

Fig. 8 shows the current in the indicator units of Fig. 6 when thepresent invention is not employed.

Fig. 9 shows the current in the indicator units of Fig. 6 in accordancewith the present invention.

Fig. 10 shows a circuit in accordance with a modified form of theinvention.

Fig. 11 shows the impulses set up by the distributor of Fig. 10.

Fig. 12 shows the current in the indicator units of Fig. when thepresent invention is not employed.

Fig. 13 shows the current in the indicator units when operated inaccordance with the circuit of Fig. 10.

Fig. 14 shows a complete transmitting and repeating system employing theinvention.

Fig. 15 shows the current through the winding of the transmitting relayof Fig. 14 as the distributor operates.

Fig. 16 shows the flux in the transmitting relay as the current impulsesare received from the transmitting distributor.

Referring first to Fig. 1, there are shown thereon two relays A and AA,the relay A being'provided with at least four pairs of contacts arrangedto close as the relay operates. The re lay AA is provided with one ormore pairs of normally closed contacts arranged to open as the relayoperates, each pair of contacts of the relay AA being operated by anarmature individual thereto and so adjusted that one of the pairs ofcontacts will be opened by the operation of its respective armaturebefore the other of the pair of contacts is opened as the coil of therelay is energized.

Referring next to Fig. 5, there is shown an incoming line L connected tothe winding of relay A, the other end of the winding being continuedthrough the break contact and armature l of the relay AA to ground.Assuming that a series of uniformly spaced signals comprising a seriesof battery impulses, each having 42% closure are applied to the line L,relay A will operate on the first of these impulses to the groundedarmature I of relay AA. As the armature 2 of relay A engages its makecontact, battery is applied to the winding of relay A from the armature2,

thereby locking relay A until relay AA is operated. As armature 3 ofrelay A engages its contact battery is applied to the winding of relayAA causing it to operate. Relay AA is slow to operate however, beingrestrained somewhat from operation by the spring 4 attached to itsarmature. The operation of relay AA causes the relay A to release and atits armature 3 open the operating path for the relay AA. As relay Amoved its armatures 5 into engagement with the contacts thereof abattery impulse was sent over the lines 6.

The second impulse is now received over the line L, but this occurs soquickly after the release of the relay A that the flux in the core ofthe coil of the relay A has not diminished to the same value as when thefirst impulse was received. The relay A will therefore operate quickeron the second impulse than when the first impulse was received. Thiscondition is shown on Fig. 3 which shows a series of uniformly spacedimpulses having 42% closure. The operate time of the relay A in responseto the first impulse is 17% and for all-succeeding impulses 14%. Theimpulses delivered by the relay A to the lines 6 are shown to be 63% forthe first impulse and 61% for the remaining impulses of the series. Itwill be noted that the open space between the first and second impulseis 34% and between all other impulses of the series the open space is39%. This is because the relay AA starts to operate 17% after the firstimpulse is received and requires 2% longer to operate on the firstimpulse of a series than on subsequent impulses of the series. When thesecond impulse is .received, relay AA has its operate circuit closed 114% after this impulse is received and operates 2% quicker than duringthe first impulse due to the residual magnetism remaining in themagnetic core of relay AA at the time the second impulse is received.This results in an open interval of 34% between the first and secondimpulses retransmitted. When the third impulse is received, the operatecircuit of relay AA is closed 14% after the impulse is received, and therelay operates in the same time that it did when the second impulse wasreceived. Since there is a difference of 3% in the operate time of relayA when the first and second impulses respectively are received, thisdifference of 3% combined with the decrease of 2% in the operate time ofrelay AA renders the interval between the second and third andsucceeding impulses 5% longer than the interval between the first andsecond impulses of a series. The open space or release time of theelectroresponsive apparatus controlled by these impulses is therefore 5%less at the end of the first impulse than at the end of each of theother impulses. The electroresponsive apparatus controlled by theseimpulses, as for example the indicator unitshown in Patent 2,067,187granted to Merton L. Haselton on January 12, 1937, depends for operationupon the movement of an armature in one direction as the coil isenergized and movement of the armature in the reverse direction by theaction of a retractile spring as the coil is deenergized. Shouldinsufficient time be allowed between the deenergization of the coil andthe succeeding reenergization thereof, the armature will not fullyrelease and the indicator will fail to operate.

The embodiment of the invention shown on Fig. 6 is a practical solutionto the problem of preventing failure of an indicator unit to operate dueto the crowding together of the first and second impulses of a series ofimpulses as in this circuit the first and second impulses have aseparation therebetween of substantially the same duration as theseparation between each of the following impulses of a series. Thecircuit of Fig. 6 provides for transmitting to the indicator unit acurrent impulse of the same strength as the succeeding impulses andmaintaining a predetermined residual fiux value in the cores of theindicator units prior to operation of the same in response to the firstimpulse so that the power developed by the armature of the indicatorunit as the first impulse of a series of impulses is received is thesame as the power developed by the armature as succeeding impulses of aseries of impulses are received. The operation of the system of Fig. 6will now be described.

The transmitting distributor TD comprises a series of equal lengthsegments 1 connected to battery and uniformly spaced one from the other.As these segments are traversed by the brush 8, a series of batteryimpulses are transmitted over the conductor 9 to the winding of therelay R a the distributor operates, the circuit being continued throughthe winding of the relay R to th break contact and armature ll of relayS to ground. The transmitting distributor TD also has a segment l2unconnected so that as the brush 8 traverses the segments 1, a series ofuniformly spaced signals of equal length are transmitted to the relay R,the series being terminated during the time the brush 8 passes oversegment I2 of the transmitting distributor. As

the relay R operated and moved its armature [3 into engagement with thecontact thereof battery from the armature I 3 of relay R was applied tothe winding of relay R to hold the relay operated during part ofthe timethe brush 8 was passing from one to another of the segments 1. Asarmature H of relay R engages the make contact thereof battery isapplied to the winding of relay S causing relay S to operate and at itsarmature remove ground from the relay R, thereby causing relay R torelease. Relay S is provided with an adjustable spring |5 whereby theoperating time of the relay S may be varied and the output pulse fromthe relay- R adjusted at will.

The resistance |6 has one end connected to battery and the other end tothe conductor 9 whereby a biasing current is applied to the winding ofrelay R when the relay S is unoperated. This biasing current is ofinsufficient strength to cause the relay R to operate. Suificientbiasing current is maintained through the winding of the relay R howeverto keep the flux in the magnet core of such a density that the time ofoperation of the relay R in response to the first impulse of a series isthe same as the time of each subsequent operation of the relay R as theremaining impulses of the series are received.

Referring to Fig. 4, the impulses transmitted by the segments 1 of thedistributor TD is shown to be 42% and the open period between theseimpulses is 58%. The operate time of relay R as the first and all othersof the series of impulses is received is 9.5% and since the transmittersends impulses at a uniform rate and the time required to operate therelay R in response to each of these impulses is the same regardless ofwhether the impulse is the first or any other impulse of a series, therelay R closes its transmitting contacts I! and 8 at uniformly spacedintervals thereby retransmitting impulses to the indicator units II andI2 at a uniform rate. The length of the first impulse transmitted by therelay R is 63% and the open period between the end of the first impulseand the start of the second impulse delivered by the relay R is 37%. Thesecond and all succeeding impulses delivered by the relay R is 61%followed by an open interval of 39%. As the relay S is first required tooperate from a fiux value of substantially zero in the core of thewinding thereof when the first impulse is received, the operate time ofrelay S in response to the first impulse is 2% greater than the operatetime of this relay as subsequent impulses are received. This conditionis the result of the flux in the relay S at the start of the secondoperation thereof being at a slightly higher residual value than whenthe first impulse to this relay was received.

The output signal of the relay R therefore is 63% for the first impulseand 61% for all succeeding impulses of a series.

The relay S is provided with an armature |9 having battery connectedthereto and normally in engagement with its contact whereby battery fromthe armature I9 is applied through the resistances 2| and the winding ofthe indicators U and 12 in parallel during the time the relays R and Sare unoperated. The indicators II and 12 are thus normally in a circuitto battery, which circuit includes the resistances 2| and the armature|9 of the relay S. The current flowing through the windings of theindicators II and 12 during the time that relays R and S are unoperatedis of suificient strength to set up a flux in the core of the windingsof these indicators of such a value that the time required to operatethe armature when the first impulse is received is the same as the timerequired to fully operate the armature when subsequent impulses of aseries are received, but the current through the resistances 2| to theindicator units is of insuflicient strength to cause the units tooperate until the relay R has operated.

The circuit arrangement of Fig. 6 provides for a decrease in the timerequired for the armatures of the indicators to fully operate therebyincreasing the speed of operation of the indicators. This condition isobtained by adjusting the relay S so that the armature |9 thereof willengage its contact approximately 20% after the contacts of relay R haveopened. This arrangement is obtained by the use of two armatures shownin Fig. 2 of the drawings, one of the armatures serving to open thelocking circuit for the relay R and the other controlling the currentthrough the resistances 2| in such a manner that the armature |9 engagesits contact and causes current to flow through these resistances notsooner than approximately 20% after the contacts of relay R have opened.The armature ll of relay S releases more quickly than the armature i9due to the force exerted by the retractile spring l5 upon the armatureN.

Fig. 7 is a diagram showing the pulses delivered by the transmittingdistributor TD of Fig, 6. These pulses for example are shown to beuniformly spaced and having a closure period of 50%, and an open periodof 50%.

Fig. 8 is a diagram showing the build up of current in the indicatorunits II and I2 of Fig. 6 when the armature |9 of relay S isdisconnected from battery or otherwise prevented from applying a biasingcurrent to the indicator units prior to their operation.

Referring now to Fig. 9 which is a diagram showing'the current in theindicator units II and I2 in accordance with the circuit of Fig. 6, itwill be noted that a value of current y normally flows through thewindings of the indicator units when no operating impulse is receivedand prior to a series of impulses. As the relay R moves its armatures l1and I8 into engagement with their contacts battery is applied throughthe resistance 22 to the indicator units thereby to cause them tooperate over a circuit including the resistances 2| and 22 in parallel.Twenty-five percent after relay R has operated, the armature IQ of relayS moves away from its normal contact thereby removing battery from oneend of the resistances 2| and causing the current in the indicator unitsto drop to the value at. When the relay R releases after havingdelivered an impulse of 61% to the 7 indicators the circuit to theindicator windings is open and the current through these windings iszero. Twenty percent later the armature I9 of relay S releases andapplies battery through the resistances 2| to the indicator unitscausing a current to flow through their windings of a magnitude y. Afterthe relay R has released 39% later,relay R again operates to transmitthe second impulse of the series of impulses in the indicator units.

It will be apparent from an inspection of the diagram of Fig. 9 and theforegoing description that a current y is applied to the indicator unitsprior to the first and all other impulses of a series and a current ofhigh intensity is applied to the Winding of the indicator units duringthe first part of the operating impulse followed by a somewhat lesservalue of current as which is subsequently applied to the units beforethe operating current has been removed. As the relay R releases andcurrent a: is removed, a no'curr'ent period follows after which thebiasing current y is again applied to the windings of the indicatorunits prior to the second operating impulse. The value of theresistances 22 determines the strength of the current 3:, Fig. 9 in thewindings of the indicator units II and I2 just prior to the time thatthe impulse thereto is removed. The current a: may be so reduced invalue by the proper selection of the resistances 22 that the flux in thecores of the indicators is of only slightly greater density than thevalue required to maintain their armatures operated so that when relay Rreleases, the release time of the armatures of the indicators will bereduced to a minimum.

The advantages flowing from this arrangement will best be understood byconsideration of the flux within the coil core of a single indicatorunit during an operating cycle thereof. Assuming, for example, that aseries of impulses such as those shown on Fig. 7 were delivered to theindicator unit in rapid succession. The first impulse would cause theflux within the core of the unit to be built up from an initial value ofsubstantially zero residual. When the flux has been built up to acertain density within the ferric circuit o the unit the armature beginsits movement toward the electromagnet. At the beginning of, the secondimpulse of the series the flux within the ferric circuit of the unit hasnot diminished to the initial value and it is desirable therefore toapply an initial current y, Fig. 9, to the winding of the indicator toestablish a flux below the value required to operate the unit and toapply a strong operating current at the beginning of each impulse sothat the flux may be built up to a density sufiicient to operate theunit with a minimum of delay after the operating impulse is received.The armature therefore starts its movement almost immediately followingthe reception of the first operating impulse and moves quickly to itsfully operated position. During this movement and before the operatingimpulse is removed, the current through the windings of the indicator isreduced, thereby to lower the flux density in the core of the unit to avalue slightly above that required to maintain the armature operated andthereby enable the armature to release with a minimum of delay after theoperating current has been removed from the winding of the unit.

The armature of the unit starts to release and during the release strokethereof the biasing current is again applied to the winding to set upflux in the core so that the armature will respond quickly to thesucceeding operating impulse of a series.

Referring now to Fig. 10 which shows a modified form of the invention,battery impulses are transmitted from the distributor TDI as thedistributor operates in a manner similar to the operation of thedistributor TD. These battery impulses cause the operation of the relayC, the circuit being continued from the winding of relay C to thecontact and grounded armature 24 of relay D. As relay C moves itsarmature 25 into engagement with the contact thereof battery on armature25 causes the relay D to operate and at its armature 24 open the lockingcircuit for the relay C, thereby causing relay C to release. Relay C hasnormally applied thereto a biasing current from battery through theresistance 26, winding of relay C, normal contact and armature 24 ofrelay D to ground, which biasing current is effective only when relay Dis released. The op- 'erate time of relay C, as has been previouslyexplained in connection with relay R, is the same for the first as forthe succeeding impulses of a series of uniformly spaced impulses and therelay C therefore at its armatures 21 delivers a battery impulse throughthe resistances 28 and 29 to the winding of the indicator units I3. Theresistance 29 may be adjusted to obtain the best operation of theindicator I3 as hereinafter described.

The relay C is also provided with an armature 30 the closure of whichapplies battery to the Winding of relay E from whence the circuit iscontinued through the winding of relay E and break contact and armature20 of relay F to ground, thereby causing relay E to operate and lock byway of its armature 3| and make contact thereof to battery. As armature32 of relay E engages its contact, battery is applied to the Winding ofrelay F, causing it to operate and at its armature 20 release relay E.Relay E is also provided with an armature 33 and a normal contact sothat the resistance 29 is in parallel with the resistance 28 when therelay E is unoperated v movement of the armature 30 of relay C intoengagement \m'ththe make contact thereof, armature 33 of relay E wasdisengaged from its contact and the resistance 29 was removed from theoperating circuit of the indicator unit. As the relay C subsequentlyreleased, the circuit to the winding of the indicator I3 was opened andthe armature of the indicator unit was permitted to release.

The diagram of Fig. 11 shows the impulses transmitted by the relay C asthe relay C operates successively. Fig. 12 shows the current in the coilof the indicator unit when the parallel circuit comprising theresistance 29 and the armature 33 of relay E is not employed. It will benoted that the current builds up slowly in the indicator unit under thiscondition due to the inductance of the coil of the indicator with theresult that the flux in the magnet of the unit builds up slowly and thearmature does not start its movement until some time has elapsed afterthe operating impulse is transmitted to the unit.

Fig. 13 is a diagram illustrating how a strong current is first appliedto the winding of the indicator unit and subsequently reduced in valuebefore the current impulse is terminated. This first high value ofcurrent causes the flux in the unit to build up very rapidly and themovement of the armature to start almost immediately after the currentimpulse is received. The reduction of the current during the latter partof the impulse causes the resultant flux in the unit to be reducedduring the movement of the armature so that as the current impulse isterminated, the

time required for the flux to diminish to a value at which the armaturestarts to release is substantially zero and the armature releases almostimmediately after the impulse has terminated.

As is well known in the operation of electromagnetic devices of thischaracter the pull exerted by the magnet upon the armature for any.given value of flux density is inversely proportional to the square ofthe distance between the armature and the end of the magnet core. If,for example, the airgap between the armature and the magnet core of theindicator unit with the armature unoperated was three times the distancebetween the armature and the magnet core with the armature operated, thepull on the armature at the beginning of the operate stroke thereof forany value of flux in the core would be one ninth of the pull exerted bythe core on the armature when the armature is in the oper ated position.It is, therefore, a decided advantage to have a flux density in themagnet coil core higher at the beginning of the operate stroke of thearmature than when the armature has completed its operate stroke inorder that the pull on the armature may be more uniform during thestroke of the armature.

This arrangement results in a faster operation of the indicator unitthan has heretofore been possible. It enables the unit to be operated bymeans of a shorter pulse than heretofore employed and because of thereduced flux in the coil core of the unit at the time the pulsingcontacts are opened, the inductance of the unit at this time isdecreased and sparking and erosion of the pulsing contacts is reducedthereby prolonging the life and adjustment of the contacts. It alsoprovides for operation of the indicator unit at lower voltages thanheretofore employed.

Fig. 14 shows another form of the invention comprising a transmitter TDZof any suitable type, a pair of transmitting relays G and H, a receivingrelay K for repeating the signals received from the relay G and aplurality of line relays L operated thereby. The operation of the relaysG and 1-1 will first be described:

As the distributor TD2 engages the first of the connected segmentsground is applied to one end of the winding of relay G causing the relayG to operate and at its armature 34 connect battery at one end of theresistance 35, thereby to operate relay H While the brush is inengagement with the first connected segment. It will be noted that withrelay H unoperated ground at its armature 36 is connected to thevariable resistance 31 and thence to the winding of the relay G, therebyto maintain a residual flux density in the relay G during the time thatimpulses are not received which is the same order of magnitude, forexample, as the flux density at the beginning of the second and allsucceeding impulses of a series transmitted by the transmittingdistributor TDZ. The relay H is a slow release relay and remainsoperated While the impulses of a series of impulses are being receivedand transmitted by the relay G. This relay may be made slow to releaseby any suitable means as, for example, by the use of a copper slug aboutthe core of the relay or by a suitable resistance 38 connected inparallel with the winding of the relay.

Fig. 15 is a diagram showing the current in the winding of the relay Gas the first impulse of a series is received. Referring to Fig. 15, itwill be noted that the current 20 flows through the winding of the relayG before the first impulse is received, which current results from thegrounded armature 36 of relay H being in circuit with the resistance 31in series with the winding of relay G. This current is determined by theadjustment of the resistance 31 and. causes the initial flux 1;, Fig.16, to be maintained in'the core of the electromagnet of the relay G ofthe' same value as the flux in the core of this relay at the beginningof the second and all subsequent impulses of the series.

As the distributor TDZ transmits the first impulse of a series, thecurve toward the left of Fig 15 rises in accordance with the value ofcurrent in the winding of relay G as the brush of the distributorcrosses the first of the connected segments. The flux in the magnet coreof this relay is shown on Fig. 16 immediately below the current waveproducing the flux. As the brush of the distributor TD2 crosses thisfirst connected segment, relays G and H operate and as the brush leavesthe first connected segment the current in the winding of the relay Gdrops to zero and the flux in relay G starts to decrease in densityuntil the brush engages the: second of the connected segments of theseries at which time the flux density will just have decreased to theinitial value c. It is apparent, therefore, that the time required forthe relay G to operate and close its contacts after the first pulse isreceived is the same as the time required after the second and allsucceeding impulses of a series of uniformly spaced impulses arereceived.

If the relay G was operated as a transmitting relay without the biasingcurrent preceding the first impulse, the time required to operate therelay in response to the first impulse received would be greater thanthe time required to operate the relay as subsequent impulses'o-f theseries were received. When the relay G was first required to operate inresponse to the first impulse of the series the residual flux in thecore of the winding would be substantially at zero value, but as thesecond and succeeding impulses of the series are received, the flux hasnot diminished to this value and the relay will operate quicker thanwhen the first impulse was received. Since the flux in the relay corereaches the same density at the end of the first impulse as at the endof succeeding impulses of a series and the release time for the relaytherefore is the same regardless of Whether the impulse causing theoperation of the relay was the first or any other impulse of the series,it is evident that the first of a series of output impulses transmittedby the relay without a substantial value of flux in the core at thebeginning of the first impulse is shorter than the succeeding outputimpulses of the series. Similarly relay K would repeat and additionallyforeshorten the first shortened impulse of a series as will relays L,the foreshortening of the first impulse being increased progressively inthe relays G, K and L as this signal is repeated by these relays. Thus,if sufficient repeating relays were operated in cascade the firstimpulse transmitted by the last relay of the cascade would be lost. Thiscondition is a frequent cause of failure of ticker or market quotationapparatus controlled by impulses.

The resistance 31 may be so adjusted that the initial fiuX in the relayG at the beginning of a first impulse of a series is higher in valuethan the flux at the beginning of the remaining impulses of the seriesand the time of operation of the relay G therefore as the first impulseis received is less than the time of operation as the remaining impulsesare received thereby causing relay G to transmit the first impulse of aseries of greater length than the remaining impulses of the series.

As the relay G moves its armature 39 into engagement with the contactthereof battery is applied over the line I to the Winding of repeatingrelay K during the time the armatures 40 transmit similar impulses tothe lines 2 and 3.

tial flux therein at the beginning of a series of impulses issubstantially at zero density and the time required to operate therelays K and L 1 as the first impulse of a series is received issomewhat greater than when subsequent impulses of a series are received.By means of the adjustable resistance 31 the operate time of the relay Gas the first impulse is received from the transmitting distributor TDZmay be made sufficiently rapid to increase the length of the firstsignal transmitted by the relay G and compensate for the delay in theoperation of the relays K andL in response to the first impulse receivedby them so that the relays L will transmit a series of uniformly spacedimpulses of equal length without distortion as transmittedby thetransmitter TD2.,

For purposes of illustration this invention has been described inconnection with a telegraph repeater controlling the operation of astock quotation system, but it obviously is not so limited, beingadapted for use in Various systems for the dissemination of information.Also, the embodiment of the invention may take other specific formswithout a departure from the spirit or principles herein described. Thepresent embodiment is therefore illustrative and not restrictive, thescope of the invention being indicated by the appended claims ratherthan by the foregoing description, and all changes within the meaning.and range of equivalency of the claims are intended to be embracedtherein.

What is claimed and desired to be secured by U. S. Letters Patent is:

1. In a signaling system, a source of signals comprising a series ofuniformly spaced current impulses of equal length, a repeating relayoperated thereby, said repeating relay having a plurality of contacts,means for causing said repeating relay to operate within the same timeinterval after the first impulse of the series is received as when eachof the remaining impulses of the series is received and for determiningthe length of the retransmitted impulses, an indicating device, meansfor causing the indicating device to operate at a relatively fast rate,said means comprising certain of the contacts of the repeating relay foroperating said device over a circuit comprising a first resistanceelement, a second resistance element normally in parallel circuit withthe said first resistance element, and means comprising a relay operatedby another contact of the repeating relay for interrupting the circuitthrough the second resistance element during the time the transmittingcontacts are closed whereby the indicating device receives more currentduring the first part of each operating impulse thereof than during thelatter part of the impulse.

2. In a signaling system, a source of uniformly transmitted signalscomprising a series of current impulses, a repeating relay controlledthereby, said repeating relay having a biasing current through thewinding thereof when the signals are not received, relay meanscontrolled by said repeating relay for interrupting the biasing currentduring the time the repeating relay is operated and for re-establishingthe circuit for said biasing current while the repeating relay isunoperated, adjustable means for controlling said biasing circuit, atransmitting contact on said repeating relay, an indicating deviceresponsive to the operation of said repeating relay, a line including aresistance element connecting said transmitting contact and theindicating device, a second biasing circuit comprising a resistanceelement, means for maintaining a biasing current through said resistanceelement and the indicating device when impulses are not received and forinterrupting said biasing current to the indicating device during thetime when operating impulses are transmitted thereto by the repeatingrelay and for i e-establishing said second biasing circuit during thetime interval between operating impulses.

3. In a system for the dissemination of information, a source of signalscomprising current impulses, an indicating device controlled by saidsignals and operable impulsively step-by-step to different displaypositions in accordance with the received signals, a relay operated bysaid signals, means controlled by said relay for controlling the lengthof the impulses supplied to said indicating device by said source andfor applying a biasing current to the indicating device before each ofthe signals is transmitted thereto and for removing said biasing currentwhile the signal is being transmitted and for subsequentlyreestablishing said biasing current during the open interval betweensuccessive signals to prevent biasing current from being applied to theindicating device during the first portion of the open interval betweensaid signals.

, 4. In a signaling system, a source of signals comprising a series ofcurrent impulses, a pair of relays concurrently operable in response tosaid impulses, a transmitting contact on the first of said relays,adjustable means on the second of said relays for controlling thesignals transmitted by the said transmitting contact, an indicator,circuit means including resistance elements for operating said indicatoras the transmitting contact is closed, means including said resistanceelements controlled by said second relay for applying a biasing currentto the indicator prior to and during the first part of each indicatorOperating impulse whereby said biasing current augments the currenttransmitted by the transmitting contact during the first part of theoperating impulse and reduces the current through the indicator to ahold value during the latter part of each impulse.

5. In a telegraph repeating system for disseminating information, a pairof repeating relays, a plurality of transmitting contacts on the firstof said relays, two armatures on the second of said relays, one of saidarmatures having adjustalble means for controlling the operation thereofindependently of the other armature, means including said adjustablearmature for controlling the impulses transmitted by the first relay, aposting device having an operating winding controlled by thetransmitting contact of the first relay, a source of biasing current forsaid operating winding, and means including the other armature of thesecond .relay for controlling the application of said biasing current tosaid winding for accelerating the operation of said posting device.

6. In a telegraph quotation system, means for transmitting a series ofuniformly spaced telegraphic impulses, a retransmitting relay responsiveto said impulses, a baising circuit for said relay including aresistance element, locking means for shunting the resistance element asthe relay operates, a pair of contacts on the relay, an auxiliary relayoperated by 'said pair of contacts, said auxiliary relay having contactmeans for interrupting the operating circuit for the retransmittingrelay, and means including said biasing circuit and means for adjustingsaid circuit interrupting means whereby the unoperated time interval forthe retransmitting relay between the first and second impulses of theseries retransmitted is substantially the same as the unoperated timeinterval between each other of a pair of successive impulses of theseries retransmitted.

'7. Apparatus for operating an electromagnetic indicating device, whichcomprises means for applying to the device a biasing current of a valueto set up a predetermined amount of flux in the device, but insufficientto cause the device to operate, means for applying to the device asignal comprising a value of current of greater strength to cause thedevice to operate quickly, means for applying another value of currentto the device less than the last named value of current, but in excessof said biasing current and having a strength sufiicient to hold thedevice operated, means for discontinuing the current applied to thedevice to quickly release the device, and means for thereafterreapplying the first named value of current to the device prior to thereoperation thereof.

8. Apparatus for operating an electromagnetic indicating device, whichcomprises means for applying to the device a current of a value to setup a predetermined amount of flux in the device, but insufiicient tocause the device to operate, means for applying to the device a signalcomprising a value of current of greater strength to cause the device tooperate quickly, means for applying another value of current to thedevice during the time the device is operating less than the last namedvalue of current, but in excess of said first named current and having astrength sufiicient to cause the device to continue operation, means fordiscontinuing the current applied to the device to quickly release thedevice, and means for thereafter reapplying the first named value ofcurrent to the device prior to the reoperation thereof.

9. In a signaling system, a source of signals comprising a repeatingrelay for receiving and transmitting a series of substantially uniformlyspaced telegraphic impulses, an indicating device controlled by saidrepeating relay, means for maintaining a flux in the core of therepeating relay prior to the operation thereof in response to the firstimpulse of the series of the same value as when subsequent impulses arereceived to operate the repeating relay thereby to maintain theoperating time of the relay constant as each impulse is received, meansfor maintaining the same value of flux in the indicating device as eachoperating impulse thereof is received from the repeating relay wherebythe operating time of the indicating device is the same for eachoperation of the device and means controlled by said repeating relay forcontrolling both of said maintaining means.

10. In an electric impulse repeating system, a repeating relayresponsive to a series of substantially uniformly spaced incomingimpulses, and means for causing said relay to retransmit said impulseswith substantially the same interval between the first two impulses ofsaid series as between any other two successive impulses of the series,said means comprising an additional relay means controlled by therepeating operad tion of said first relay for controlling the length ofthe impulses retransmitted by the first named relay and means comprisinga circuit controlled by said additional relay means for applying abiasing current to the winding of said repeating relay prior to andduring the reception of at least the first portion of each impulse ofthe series and for removing said biasing current from the winding ofsaid repeating relay during the operation of said relay means forcontrolling the length of the impulses retransmitted.

ERNEST FRISCHKNECHT.

